1. Field of the Invention
The present invention relates to a seal container, more particularly one, which includes a seal member for a container body, and a knob usable for changing the seal member to a sealing shape as well as an unsealing shape, and which is structured in such a way as to be convenient to use and have extended service life.
2. Brief Description of the Prior Art
Referring to FIGS. 1 and 2, a conventional seal container includes a lid 10, a soft seal member 20, and a container body 30. The lid 10 has cavities 101, and a through hole under the cavities 101. Two pressing elements 102 are held in the cavities, and pivoted to the lid 10. The soft seal member 20 is fitted over a lower end of the lid 10 to face the through hole of the lid 10 at a middle portion. The pressing elements 102 will be away from the soft seal member 20, and the seal member 20 will be in a normal shape, in which shape it can stretch and closely touch an inner side of the container body 30 to seal the container body 30, if the pressing elements 102 are not pushed towards each other at upper ends thereof. And, the soft seal member 20 will be made to reduce in circumference, and can't touch the inner side of the container body 30 closely any more when the pressing elements 102 are pushed towards each other at the upper ends so as to depress the middle portion of the soft seal member 20.
The above seal container has the following disadvantages:    1. It is difficult to make a mold for the lid 10 because the lid 10 has the cavities 101.    2. Dust will accumulate in the space between both of the pressing elements 102 as well as the space between the pressing elements 102 and the lid 10, and the lid 10 is difficult to clean because of the structure. And, dust will drop onto the soft seal member 20 while the pressing elements 102 are being moved. Consequently, smoothness of movement of the pressing elements 102, and sealing capability of the soft seal member 20 will gradually reduce.    3. The user has to exert relatively large force on the pressing elements 102 otherwise the soft seal member 20 can't be effectively reduced in the circumference to change to the unsealing position. In other words, the seal container isn't convenient to use.
Referring to FIGS. 3 and 4, another conventional seal container includes a lid 40, a knob member 50, a soft seal member 60, and a container body 70. The lid 40 has a central hole 401, a touching portion 402 around the central hole 401 on a lower side, and a stopping portion 404 on the lower side, which touching portion 402 is formed with several slopes 403 of equal length on a lower end thereof. The knob member 50 has a middle portion, several spaced touching blocks 501 next to the middle portion, and a stopping projection 502 on an edge. The knob member 50 is up and down movably passed through the central hole 401 of the lid 40 at the middle portion with the touching blocks 501 touching respective ones of the slopes 403 of the lid 40. Thus, the knob 50 will be in a higher position after it is turned such that the touching blocks 501 thereof touch higher ends of the slopes 403, and it will be in a lower position after it is turned such that the touching blocks 501 thereof touch lower ends of the slopes 403; the stopping projection 502 will come into contact with one end of the stopping portion 404 of the lid 40 as soon as the touching blocks 501 touch the lower ends of the slopes 403 of the lid 40, and it 502 will come into contact with the other end of the stopping portion 404 as soon as the touching blocks 501 touch the upper ends of the slopes 403.
The soft seal member 60 is fitted over the lower side of the lid 40, and has bumps 601 spaced apart on an edge of a lower side thereof, every two adjacent ones of which define a space 602 in between. The container body 70 has several bumps 701 spaced apart on an inner side thereof. When the lid 40 is used to cover the container body 70, the bumps 701 of the container body 70 will be held in the spaces 602 of the soft seal member 60.
And, the seal member 60 will be in a normal shape, in which shape it can stretch and closely touch the inner side of the container body 70 to seal the container body 70, when the knob member 50 is in the higher position. And, the soft seal member 60 will be depressed at the middle portion by the knob member 50, and reduced in circumference, and can't closely touch the inner side of the container body 70 any more when the knob member 50 is in the lower position. Thus, the container body 70 will be sealed with the seal member 60 as soon as the knob member 50 is turned so as to move to the higher position after the container body 70 has been covered with the lid 40. And, the lid 40 can be easily fitted in, and removed from the container body 70. after the knob member 50 is turned so as to move to the lower position.
In the second seal container, knob member 50 is used instead of pivotal pressing elements 102 as the means used for reducing the soft seal member therefore the second seal container is more convenient to use than the first one. However, the second seal container still has disadvantages as followings:    1. Dust is likely to accumulate in the central hole 401 of the lid 40 and between the touching blocks 501 and the slopes 403 because the knob member 50 will move up and down relative to the lid 40 when it is used. Consequently, smoothness and range of movement of the knob member 50 will gradually reduce, and the seal member 60 can't have enough sealing capability.    2. Because of the engagement of the spaced bumps 601 of the seal member 60 with the spaced bumps 701 of the container body 70, when the knob member 50 is used, the lid 40 is prevented from turning relative to the container body 70; thus, the knob member 50 can be easily displaced relative to the lid 40. However, the bumps 601 will wear owing to external force thereon that is caused when the knob member 50 is turned, therefore they get damaged after the seal container is used for a certain period of time. Consequently, the bumps 601 and 701 can't prevent the lid 40 from turning relative to the container body 70.    3. Because of the range of movement of the knob member 50 is limited by means of two ends of the stopping portion 404 of the lid 40, the user has to turn the knob member 50 in a reverse direction to move the same back to the higher position after the knob member 50 is used to depress the soft seal member 60. Consequently, the seal container isn't convenient to use.